Pressure actuated switches



Jan. 19, 1960 K. M. DANIELS 2,922,001

PRESSURE ACTUATED swrrcmzs Filed June 17, 1957 7 5 l l3 l9 .,/1) ll 8 z 43 45 1 4- I 4? s 45 KENNETH M. DANIELS. 45 43 s2 30 5 7 s O a I 52 51 9; JI36 as BY if ATTORNEY.

United States Patent 2,922,001 PRESSURE ACTUATED swrroHEs KennethM. Daniels, Los Gatos, Calif. 7 Application June 17, 1957, Serial No. 666,172

' 2.01am. Cl. zoo-s3 This invention relates to pressure actuated switches and deals with features designed to increase the sensitivity, accuracy and dependability of switches of this type.

Pressure actuated switches have a great many uses, some of which require service under a wide temperature range. Others are required to work under extremely rugged conditions. But the prime requirements under all conditions are sensitivity, accuracy and dependability. Accuracy in thefinal analysis means sensitivity, and sensitivity should be adjustable to render a pressure actuated switch suitable for use in different fields.

My invention provides a pressure actuated switch in which the sensitivity may be adjusted to suit various requirements. Under this arrangement, the same switch may be used for a great many different purposes and under many variable conditions. Also, it follows, that the same switch may be used with a minimum of pressure, thereby increasing the sensitivity.

Briefly stated, my invention includes a suitable diaphragm in combination with a cantilever arm arranged to be depressed by the diaphragm to open or close the contacts of a switch, together with a sliding fulcrum for the arm to vary the bending moment of the arm and thus regulate the force required from the diaphragm to operate the switch.

Other features of my invention reside in the provision of a switch of the pressure actuated type in which the body of the switch is small, compact, light weight, hermetically sealed, good workmanlike appearance, durable, and altogether suitable for the purpose described.

Other objects and advantages will appear as the description proceeds in conjunction with the drawing in which:

Fig. l is a side elevation of my switch;

Fig. 2 is an end view of Fig. 1, taken in the direction of the arrow 2;

Fig. 3 is a top plan view of Fig. 1;

Fig. 4 is a plan view of the under side of the top part of the device carrying the diaphragm, taken on line 4-4 of Fig. 1;

Fig. 5 is a sectional view taken on line 55 of Fig. 3;

Fig. 6 is a top. plan view of the lower half of the device carrying the switch contacts and the cantilever arm, taken on line 6-6 of Fig. 1.

Referring to the drawing, it will be seen that my device consists of two parts, generally designated D, the cover carrying the diaphragm, and S, the body carrying the cantilever arm and the switch contacts. These two units are made separable as a part of the novelty of my invention and are mountable .upon each other by any suitable means such as by a fiange 11 having screws 12 conveniently placed therein.

The cover D may take a variety of forms but in following the intent of my invention to make a light device, I form the cover into a casing having a circular chamber 13 embodied therein. A passage 14 leads into the chamber and the outer end of the passage is equipped with screw threads 15 to receive a fitting 16 for connecting a lead in pipe 17 for supplying fluid under pressure to the chamber. Across the open end of the chamber 13, I mount a diaphragm 18 on an annular shoulder 19 cut in the casing D. The diaphragm 18 is held in place by a dish shaped plate 20 which, in turn, is held in place by a snap ring 21 mounted into an annular groove in the wall of the chamber opening. The diaphragm 18 carries a centrally positioned push pin, generally designated 22, which is suitably attached to the diaphragm in any suitable manner such as by washers 23 and a screw 24. The lower end of the push pin is tapered to a small point 25 to provide a concentrated point at which the pressure from the diaphragm is brought to bear on the cantilever arm, to be later described. The foregoing described construction is all part of the cover casing and removable therewith.

The body S, as shown in Figs. 5 and 6, is seen to consist of a casing 26 of suitable material having a top surface 27 adapted to receive the flange 11 of the cover D and form a good fit therewith. The casing 26 is further formed with two chambers 28 and 29. It will be noted that the bottom of the chamber 28 is belo'w that of the chamber 29. In the bottom of chamber 28, I mount the switch contacts.

For the purpose of illustration, I have shown a simple form of switch contacts. It is to be understood, however, that the invention is not to be limited to the contacts shown as I may use the common variety of switch known as the micro-switch, or. something similar already made up with a make and break arrangement operated by a push button. Also I may use my invention to open a switch, instead of closing it equally as well by merely reversing the switch action. As shown the switch consists of a piece of insulation 30, especially shaped, mounted in the bottom of the chamber 28. This may be held in place by screws 31. A spring finger 32 is mounted on v the lower face of the insulation 30 and held in place by a screw 33. An upper spring finger 34 is mounted on a shoulder of insulation above the finger 32 and held in place by a screw 35. A wire 36 connects the contact 32 with a terminal 37 upon which is exteriorly mounted a clip 38. Similarly a wire 40 connects the contact finger 34 with a terminal 42 upon which is exteriorly mounted a clip 42. Upon contacting the two fingers 32 and 34 a circuit is completed through the clips 38 and 42 which is the function of the switch.

The force for bringing the spring fingers together is supplied through the push button 22 on the diaphragm, which in this case, depresses the top finger 34 against the lower finger 32. The pressure from the diaphragm is transmitted through a cantilever arm, generally designated 43 which is rigidly mounted in the chamber 29 on a button 44 held in place by a screw 45 and extends over the chamber 28. As shown, for purpose of sensitivity, the arm is made slender for a portion of its length at 46, and at the outer end carries an insulation button 47 to insulate the circuit away from the casing S. To provide the novel feature, before mentioned, of regulating the sensitivity of the device, I provide a sliding fulcrum for the arm 43. This consists of a plate 48 adapted to move the bottom of the chamber 29, said plate having a knife edge support 49 arranged to engage and support the arm 43 at its slender portion 46. The means for moving the plate 48 along the bottom of the chamber 29 comprises a bolt 50 screw threadedly mounted in a boss 51 on the plate 48. The bolt 50 is journalled in the body S at 51a and is provided with a slotted head 52. A slotted nut 53 screw threadedly mounted in the body S holds the bolt 50 in the body against longitudinal movement. To adjust the position of the fulcrum point along the arm 43, the nut 53 is removed and the bolt 50 Patented Jan. 19, 1960 turned in the directiondesir'ed by the head 52 until the I proper adjustment is reached whereupon the nut 53 is again mounted in the body and the adjustment remains fixed. This adjustment can be made without interrupting or disconnecting the switch' inany manner and at the option of the operator can be made a" very fine adjust r'nent or one over a wide range.

Referring to Fig. 5, it will be seen D is mounted on the body S, the point 25 on the push button 22 enters the hole 54 on the arm 43. When in this position with the cover clamped in place; the switch is ready to operate. t

I claim:

'1. A pressure actuated switch epm srisin'g a. easing, I a diaphragm mounted in said first cas'ingQ'a push pin operably mounted on said diaphragm, means for admitting fluid'under pressure to said diaphragm, a second casing, means for mounting said, first casing on said second casing, said second casing having two chambers of different depths in the face adjoining said first casing, a spring member fixed at one end in the shallow chamber and spaced above the floor thereof substantially parallel thereto, said spring member having the free end extending over the other of said chambers adapted to' Be engaged by said push pin, a switch contact member mounted in the bottom of the deeper of said chambers, a second that when theicover v switch contact member mounted above said first contact member, said second contact member being resilient and adapted to be engaged by the said spring member and be depressed thereby to foroe said resilient member into contact with said first mentioned contact member, a sliding member between the floor of said shallow chamber and said spring member adapted to form a fulcrum for said spring member, and means for moving said sliding member longitudinally of said spring member to vary the fulcrumpoint of said spring member:

2. The elements of claim I wherein the last mentioned means consists of a screw threaded ro'd;working in a screwthrea ded hole in said sliding member, saidrod extending through the wall of said'sec'orid casing to provide adjustment of said fulcrum point externally of said casing.

References Cited in thefile of this patent UNITED STATES PATENTS 2,579,717 wood Dec. 25, 1951 

